Foreword - Encyclopedia of Social Insects, Starr, C. (Ed.) Springer International Publishing, Switzerland

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Encyclopedia of Social Insects
Edited By Christopher K. Starr.
Springer Nature, Switzerland AG. 2021.
Foreword
By Raghavendra Gadagkar
Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
The Biblical proverb, Go to the ant, thou sluggard; consider her ways, and be wise, epitomizes
human attitude toward the social insects throughout much of history. The societies of insects
have inspired us to draw lessons, issue injunctions, influence politics, and formulate moral
principles. And yet, much of this has been based on partially correct, incorrect, and sometimes
dead-wrong ideas about the biology of social insects.
A particularly embarrassing example concerns the uncritical assumption, held by
almost everyone until as recently as early eighteenth century, that the queen of the honey bee
colony must be a king, and, to make matters worse, the use of that mistaken identity to deprive
women of a place in public and political life. The “leader of the beehive” is neither a male, nor
indeed a leader, in almost any sense of the term. Most complex behavior in social insects is
self-organized in a decentralized, bottom-up manner, with little scope or evidence of top-down
control. The metaphoric transfer of power from the males to the females and from the royalty
to the subjects is the result of two centuries of the scientific study of insect societies presented
in this encyclopedia.
Social insects—ants, bees, wasps, termites, and a few aphids, thrips and beetles -
account for about 2% of the approximately one million species of insects described so far.
Despite this modest taxonomic representation, social insects, especially ants and termites, are
among the most evolutionarily successful and ecologically dominant species on earth,
estimated to comprise up to three quarters of the total animal biomass in some tropical forests.
They are found in virtually all land habitats worldwide where insects abound.
The Earth is estimated to harbour some 10 trillion ants that together weigh about as
much as all 7.4 billion humans. The success of social insects is attributed to their ability to
cooperate and form large colonies, with division of labor, communication and the propensity
for individual members to sacrifice their reproductive success and even their lives in the
interests of the colony. Equally important is their ability to build elaborate nests and achieve
impressive climate control. With few exceptions, members of a colony are not a clone, but they
have nevertheless evolved elaborate mechanisms for conflict management.
One important reason for our interest in social insects is that we depend on some of
them for our welfare. A third of our agriculture and food production, especially fruits,
vegetables and nuts, crucially depends on the pollination services rendered by honey bees and
bumble bees (as well as many solitary bees), the global economic value of which has been
estimated at US$577 billion annually. In recent decades, bee populations have declined
worldwide and therefore their services have been under great threat, endangering our food
security and global peace, ironically caused by over-exploitation and mismanagement.

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The blame for the havoc caused by importing the Varroa destructor mite to regions of
the world where honey bees are not adapted to co-exist with it, and more generally, for the so-
called Colony Collapse Disorder, can be laid straight at our doorstep. We have unsuccessfully
attempted to make honey bees live life in the fast lane, under crowded conditions, with frequent
transportation over thousands of kilometers, exposed to multiple pesticides, faced with
diminished diversity and abundance of nectar and pollen-producing plants, and forced to invest
more in honey production than in colony maintenance and reproduction. We erroneously
believe that we know best how honey bees should organize their lives, and have only recently
begun to understand how millions of years of evolution have shaped their sustainable lifestyles
in the wild. It is time we learn from the bees rather than attempt to teach them. This will need
learning much more than we know already and, more importantly, disseminating the little
knowledge that we already have as widely as possible.
We are also interested in social insects because we fear them. Leafcutter ants have been
important to the economy of Latin America since historical times to the present, being the most
important herbivores in the region, devastating more vegetation than any other animals and
causing destruction worth billions of dollars. The battle between humans and leafcutter ants is
a unique one—the ants steal the products of our agriculture not just to feed on them but to use
as raw material to sustain their own agriculture—making them the kind of enemies that demand
our respect and admiration. Leafcutter ants have been practicing the cultivation of fungi in their
gardens for over 50 million years. The secrets of their success in achieving sustainable
agriculture, some of them worthy of emulation, are only now being discovered.
The fire ant Solenopsis invicta, innocuous in its native South America, has become
famously invasive in the Southeastern United States, Australia, China, and Taiwan. It is a major
health hazard in the USA requiring the expenditure of over $5 billion annually toward damage
control, suppression and medical treatment. In a failed attempt to breed a honey bee that
combines the industriousness of the African bees with the gentleness of the European bees,
scientists inadvertently produced and released and/or let escape, a hybrid that is highly
defensive toward humans and native bees. This hybrid bee spread through South and Central
America in the 1990s at a rate of 300 to 500 km/year, reaching densities of 6 colonies per km
that translate to about a trillion bees. Some termites are another kind of serious social insect
pest, damaging buildings, wooden structures and crops and requiring billions of dollars in
expenditures, while also bringing about significant environmental pollution on account of the
chemicals used to control them.
Beyond the love-hate relationship, most of us will admit to a sense of wonder and
amazement at what our objects of study are capable of. Ant, bee and wasp queens gather sperm
from their mates, store and nourish them in their bodies for years and even decades, and then
use them to make daughters, or not use them, to make sons, giving them complete control over
the sex of their offspring. The pheromone trails of ants guide them to distant locations of food
and back to their nests.
When ants lacking trail pheromones have to relocate their nests, some of them
spontaneously emerge as leaders carrying or tandem-running their nestmates to the new nest
site. When ants, bees and wasps walk or fly out in meandering paths, they continuously update
information about their linear and angular displacement using the sun and other celestial cues,
polarized light and landmarks, after which they can walk or fly straight back to their nests.

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Honey bees go a step further and communicate the distance and direction to food
sources by means of a dance language, the discovery of which brought a Nobel Prize to social
insect research. Honey bees also make the ultimate altruistic sacrifice in defense of their
colonies—because they are unable to withdraw their barbed stings when attacking humans or
other vertebrates, so that their abdomens rupture, fatally. The Argentine ant Linepithema
humile forms supercolonies with billions of workers spread over 6000 km of coastline from
Italy to Spain.
In addition to immune defenses of individual members of their colonies, social insects
have a whole tool-kit of social immunity. The most remarkable feature may be the fine balance
they achieve between their first line of defense -- maintaining nest hygiene to prevent the spread
of infection -- and a final line of defense by killing and removing infected members.
Social insects have been at the forefront of the development of evolutionary theory.
Charles Darwin worried about the “neuters” (i.e., workers) as a potential “insuperable
difficulty” for his theory of evolution by natural selection. He proposed a way around it that
is the forerunner of the modern theory of group selection. JBS Haldane, while contemplating
how many brothers would he have to save from drowning in order to make it worthwhile to
sacrifice his life, quickly turned his attention to honey bees and realized they might be more
prone to sacrificial behavior.
William D. Hamilton drew inspiration from social insects, especially the social wasps
that he observed in Brazil, to develop his theory of inclusive fitness, also known as kin
selection. Recent controversies regarding the relative roles of individual, kin, and group
selection have led to the development of multilevel selection theory. Because the evolution of
altruism by natural selection remains a major unsolved paradox, social insects are still in the
front lines of the elaboration of evolutionary theories, their controversies and their resolution,
and will thereby throw much light on the rest of the living world.
Complex social behavior, including communication, transport and the mind-boggling
nest architecture so characteristic of many social insects, result not from superior conventional
intelligence of individual members of their societies but through a process of decentralized
self-organization—individual insects follow simple local rules that nevertheless result in the
emergence of complexity. This knowledge has most surprisingly impacted science and
technology well outside the social insect world and indeed outside biology.
The development and application of ant, bee, wasp, and termite-inspired procedures
and algorithms in computer science, transportation, telecommunications, the internet, and
robotics has been an unforeseen consequence of curiosity-driven research on social insects and
their ways of solving their own day-to-day problems. To take another example, ant and honey
bee queens can provide new insights for the study of ageing and senescence. While ant and
honey bee workers have a natural life span in the order of a few weeks, their queens, who
develop from the same genomes, can live for years and sometimes for decades. Even among
honey bee workers, summer bees age faster than winter bees and forager bees faster than nurse
bees. Their long and flexible life spans make social insects attractive and as yet poorly explored
model systems for understanding the nutritional, physiological and molecular modulation of
ageing and senescence.
Social insect science is poised to make even greater contributions to the growth of
knowledge and technology in many different areas of human activity. To facilitate this, we

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need to provide easy access to our growing understanding of the world of insect societies to a
wide audience who may never care to call themselves biologists, let alone entomologists. The
Encyclopedia of Social Insects is designed to fill this very need. In a decentralized, self-
organized manner, befitting the insect societies, the International Union for the Study of Social
Insects (IUSSI) has undertaken as a community project the production of this compendium of
our current knowledge about social insects, as well as social spiders, the result of which you
now have before you. Perhaps it’s time to rephrase the Biblical proverb and say: Go to the
Encyclopedia of Social Insects, thou curious one; consider its contents, and be enlightened.